In the opening scene of NON-STOP, federal air marshal Bill Marks is sitting in his car in the parking lot of the New York airport before he enters the building to take his flight. As he fidgets with his phone, making one last call before departing, he turns the radio on. The radio voices just happen to be discussing the issue of airport security in the post 9/11 world. Fast forward to ninety minutes later when the mystery of the film is solved and the dead and alive are separated and the television is on. The newscaster, mic in hand, looks us straight in the eyes and, under the guise of national news, explains what we have just witnessed. She clarifies the twists of the film with sincerity and merrily wraps up by tying everything with a bow. As the title suggests, subtlety is not Non-Stop’s strongest suit, but it is precisely the combination of ridiculous and grandiose that makes it such an enthralling experience.

Liam Neeson, in the latest episode of the subtextual franchise which reinvents him as America’s unlikelies action star, stars as Bill Marks (that name!) an air marshal who has been assigned to a New York to London flight. Also on the plane: Jen Summers (Julianne Moore) a seemingly nervous woman intent on finding a window seat – she ends up in the one next to agent Marks, a school teacher named Bowen (Scoot McNairy), an NYPD officer named Austin (Corey Stoll), Michelle Dockery and Lupita Nyong’o as flight attendants, and a seven year old girl called Becca, whose first interaction with Marks screams "Emotional Subplot!" thousands of miles ahead of its destination.

In an introductory conversation between Jen and Bill, it transpires that she is sheepish about revealing her occupation and he suffers from avophobia. Immediately afterwards, Marks receives a message on his secured, government provided cell phone. The message indicates that every 20 minutes, a passenger is going to be killed on the plane unless $150m is transferred to a certain bank account. Though this seems like an improbable plan given the closed environment of the plane, the first victim loses his life before Marks’s timer goes off exactly at 20 minutes. Marks tries to keep this hidden from the passengers, but subsequent accidents make this impossible. Meanwhile, he tries to convince his supervisors that the threats must not be taken lightly, but the only passenger they become suspicious of is the only man who legally carried a gun on the plane: Federal Marshal Marks.

A ludicrously contrived plot, yes, but the twists are perfectly worked out. For a narrative that hinges entirely on how the mystery is solved, rather than where the film ends, the writers avoid every possible pitfall. This isn’t to say that there aren’t any holes in its logic since it's a slice of Swiss cheese throughout. Yet, Non-Stop is successful because it stops just short of taking itself seriously while delivering an edge of your seat whodunit. The trick is in understanding that none of this could happen in the real world, but embracing it wholeheartedly, balls to the wall.

Non-Stop winks at the audience where other films would stare you straight in the eye, puffing themselves up, which is precisely why you forgive it its excesses. In a self-serious film a man jumping horizontally to grab a gravity-defying pistol mid-air would win a groan out of the audience, here it gets a “Fuck Yeah!”. An overtly politically correct casting of the one bearded, fez-wearing Muslim passenger as the life-saving doctor, comes across as a playful note in this context. It is almost as if the writers are saying “You didn’t think we’d take clarity this far; you were wrong.”

It helps that the entire supporting cast, while having nothing remotely resembling a fully formed character to play, are believable enough both as suspects and as innocent passengers. Whether they are embodying an archetypal idea or just an unassuming presence, each of them gives the film another probable twist, and those exciting possibilities are like extra snacks slipped your way by a friendly flight attendant (thanks for the peanuts!) Where the film falters is Collet-Serra’s direction of the action sequences. Though there are only a few of them throughout the film – and for the better, since the suspense is dependent on the lack of action – almost every opportunity for a classic action scene is blown with typically shaky camera work and chaotic editing. Each of these sequences is a nail-biter but their intensity is a consequence of our engagement with the story, not of their visual identity or construct. There are two scenes, however, that almost redeem the failure of all instances of blurred vision and millisecond cuts: the first is the aforementioned shooting battle and the other, a hilariously over the top end to Marks’s nascent parental relationship with Becca.

The Liam Neeson action franchise, which has no continuity or repeated characters beyond Liam Neeson as the anti-heroic hero with maybe a convenient subplot involving a troubled family history, is more likely to be remembered as a whole than for any individual entry. Non-Stop is neither substantial nor original enough to change that. But though its political message is blatant and its emotional overtones thicker than syrup, the intensity and thrill of spending two hours in front of the screen as it unravels is nearly unmatchable. In that sense, it is reminiscent of last year’s Fast 6, another film with an unrealistic story and contrived action sequences that manages to exceed the amount of pleasure one expects to derive from it despite the limitations of its plot and its adherence to the trappings of the action genre.

Just finished watching it. Not disappointed because it's exactly what I hope it to be: non-stop of thrill and action. Don't quite understand why an actress who's winning Best Supporting Actress in two days time making an appearance for two minutes screentime doing nothing but looking confused and running around the plane.

I thought it was useful that Moore and Neeson had worked together before (in Atom Egoyan's "Chloe"). They had an easy camaraderie and actor's shorthand in a movie that didn't have a whole lot of character development. It's not that kind of movie.

I liked the brief moment where the two flight attendants walked down alternate aisles, and you could see Lupita sashay like she was on the red carpet, while Michelle glided like she was still wearing an Edwardian gown.

It is every bit the improbable pot boiler I thought it would be but in the very best of ways, and I found myself completely engaged with all of the major supporting players (sidebar: Corey Stoll=swoon).